How much is a 1975 Un peso worth?

Answer 1

If it's from Mexico the honest answer is "not much". Mexico's currency plummeted in value due to inflation during the 1980s, so much so that its old currency was withdrawn from circulation and replaced in 1992-93. Old pesos (noted with the "$" sign, just like U.S. dollars) were exchanged for new pesos at the rate of 1000 to 1. The current exchange rate roughly 10 new pesos to one U.S. dollar, so old pesos traded at as little as 1/10,000 of a dollar.

That is, one old peso is worth about 1/100 of a U.S. cent.

Answer 2

AnswerI've been doing the math(calculator)and it is 0.0776 U.S.D.